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प्रश्न
Complete the following table:
| Instrument | Number of Convex Lenses |
Use |
| Simple Microscope | .............. | .............. |
| Compound Microscope | .............. | .............. |
| Telescope | .............. | .............. |
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उत्तर
| Instrument | Number of Convex Lenses |
Use |
| Simple Microscope | 1 | Used by watch repairers to view tiny watch parts |
| Compound Microscope | 2 | Used by watch repairers to view tiny watch parts |
| Telescope | 2 | Used to view faraway objects in outer space |
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संबंधित प्रश्न
(a) Draw a ray diagram to show the formation of image by a concave lens when an object is placed in front of it.
(b) In the above diagram mark the object distance (u) and the image distance (v) with their proper signs (+ve or –ve as per the new Cartesian sign convention) and state how these distances are related to the focal length (f) of the concave lens in the case.
(c) Find the nature and power of a lens which forms a real and inverted image of magnification –1 at a distance of 40 cm from the optical centre.
An object 5 cm is placed at a distance of 20 cm in front of a convex mirror of radius of curvature 30 cm. Find the position, nature and size of the image.
"A lens can form a magnified erect image as well as magnified inverted image of an object placed in front of it." State the nature of this lens and draw ray diagrams to justify the above statement. Mark the positions of O, F and 2F in the diagram.
An object is placed at a distance of 12 cm from a convex lens of focal length 8 cm. Find :
1) the position of the image
2) nature of the image
The diagram given alongside shows a ray of light entering a rectangular block of glass.
(a) Copy the diagram and draw the normal at the point of entry.
(b) Draw the approximate path of the ray of light through the glass block and out of the other side.
f the image formed by a convex lens is of the same size as that of the object, what is the position of the image with respect to the lens?
Fill in the following blank with suitable word:
Parallel rays of light are refracted by a convex lens to a point called the ........
An object is placed f and 2f of a convex lens. Which of the following statements correctly describes its image?
(a) real, larger than the object
(b) erect, smaller than the object
(c) inverted, same size as object
(d) virtual, larger than the object
The focal lengths of four convex lenses P, Q, R and S are 20 cm, 15 cm, 5 cm and 10 cm, respectively. The lens having greatest power is :
(a) P
(b) Q
(c) R
(d) S
Draw a diagram to represent the second focus of a convex lens.
A converging lens forms the image of an object placed in front of it, beyond 2F2 of the lens. Draw a ray diagram to show the formation of the image.
The given below figure shows an object OA and its image IB formed by a lens.
i. Which type of microscope has the arrangement of lenses shown in the adjoining figure?
ii. Label the figure correctly.
iii. Write the working of this microscope.
iv. Where does this microscope used?
v. Suggest a way to increase the efficiency of this microscope.
A lens always forms an image between the object and the lens.
A lens always forms an image between the object and the lens.
State two applications of a convex lens.
What is the difference between a double convex and a bi-convex lens?
State the position of object, position of image, nature of image when: Convex lens is used as an erecting lens in terrestrial telescope.
Simple microscope : Number of convex lens one : : compound microscope : _______
Differentiate convex lens and concave lens.
Distinguish between Concave lens and Convex lens.
